In the underground powerhouse of Nanzhang Pumped Storage Power Station in Hubei Province, engineer Li Zhenhua is staring at the jumping data on the monitoring screen - the rock half porosity is 99.2%, and the average overexcavation is only 8 centimeters. These numbers mean that even in broken rock formations, we can 'carve' almost perfect underground spaces. Behind him, the huge cavern is brightly lit, excavators roar, and this 1.8 million kilowatt power station is steadily moving towards its 2028 production target with millimeter level accuracy.

Thousands of miles away in Golmud, Qinghai, at a construction site with an altitude of over 3500 meters, a Tibetan young man asked Dorje to rub his frozen red hands and take a photo in front of the banner excavated on the fifth floor of the main factory building. Previously, there were only desert sandstorms here, but now we need to build the world's highest altitude pumped storage power station, "he said proudly." In the future, all the extra electricity from photovoltaic wind power can be stored here

Cracking the Secrets of Complex Geology

Pumped storage power stations are like 'skyscrapers' built underground, but the drawings are hidden in the rock layers and can change at any time, "said Wang Lei, the chief engineer of the Nanzhang Power Station project. The maximum burial depth of the underground powerhouse of the power station exceeds 300 meters, and the surrounding rock is broken like "sandwich biscuits". In the early stage of construction, water seepage or local collapse may occur after each blasting.

To this end, the project department has launched the "Three Gorges Experience" magic weapon: for each excavation section, advanced geological drilling is used to "check the pulse", combined with 3D modeling analysis, to predict the rock mass conditions ahead; During excavation, smooth blasting technology is used to control the amount and angle of explosives, reducing disturbance to the preserved rock mass; Support closely follows excavation, with high-strength anchor rods and sprayed concrete quickly forming a protective shell on the exposed rock surface. Nowadays, the excellent rate of the top arch units of the main power plant building, main transformer tunnel, and tail gate chamber has reached 100%, and the rock half hole rate, flatness and other indicators have reached the standards of high-quality engineering.

Similarly, there is also the Chongqing Fengjie Caiziba Power Station that engages in a battle of wits and courage against rocks. It is adjacent to the world's largest karst funnel, the "sinkhole and fissure", with underground rivers and caves densely distributed, making it a "hole in a honeycomb". Engineer Zhao Quanying and his team innovatively adopted the triple method of "geological analysis+advanced drilling+indoor experiments" to determine the direction of karst pipelines like doing CT scans. We have prepared grouting materials and emergency plans in advance. When encountering karst caves, we will fill and reinforce them, and when encountering underground rivers, we will divert and block them. Currently, the ventilation and safety tunnel of the power station has been successfully advanced for 400 meters and is expected to be completed by the end of August 2026.

The most challenging altitude in the world

If the power stations in the central and eastern regions are "embroidered" in complex geology, then the Golmud pumped storage power station in Qinghai is "climbing" in extreme environments. The high altitude, low oxygen, and low temperature above 3500 meters make every project here full of challenges.

The mechanical efficiency decreases, personnel physical energy consumption is high, and the concrete solidification time is different, "said Liu Yuanzheng, the on-site manager. The installed capacity and regulating storage capacity of the power station are the highest in the world at the same altitude, and after completion, it can greatly improve Qinghai's new energy consumption capacity. In January of this year, the power station reached a critical milestone - the excavation of the fifth floor of the main and auxiliary powerhouses was completed, which means that more than half of the underground engineering has been completed. The project department ensured the safe progress of the project by adding oxygen supply equipment, adjusting work shifts, and optimizing concrete formulas. At present, large-scale filling of the upper and lower reservoirs of the power station has been initiated, and the first unit is expected to be put into operation in 2027.

Under the plateau, the mountains and waters of Jiangnan are equally bustling. Unit 2 of Zhejiang Tiantai Pumped Storage Power Station has recently completed a 15 day trial operation and officially started generating electricity; The first unit seat ring snail shell of Songyang Power Station passed the water pressure test; Anhui Shitai Power Station has completed the hoisting of the second unit's seat ring snail shell... Along the Yangtze River, the pumped storage network is accelerating its densification.

The trillion dollar energy storage industry is accelerating its growth

2026 is the starting year of the 15th Five Year Plan, and pumped storage energy, as the "stabilizer" of the new power system, its strategic significance is increasingly prominent. According to data from the Energy Storage Committee of the China Energy Research Association, by the end of 2025, China's installed capacity of pumped storage has exceeded 80 million kilowatts, with a construction scale of approximately 120 million kilowatts, both ranking first in the world.

These projects not only solve the problem of power grid peak regulation, but also drive local investment, employment, and industrial upgrading, "said the person in charge of Three Gorges Group's pumped storage business. Taking Zhangye Power Station in Gansu Province as an example, after the upper and lower reservoirs are filled to the top, it is about to enter the stage of mechanical and electrical installation, and the entire project has absorbed more than 2000 local employment. The comprehensive construction of power stations such as You County in Hunan and Songyang in Zhejiang will further drive the related industrial chains of steel, cement, and equipment manufacturing.

Technological innovation is also advancing synchronously. The intelligent support system of Nanzhang Power Station, karst detection technology of Fengjie Power Station, and high-altitude construction standards of Golmud Power Station have all formed a complete set of construction methods. In the future, we plan to promote a digital construction platform to achieve intelligent management of the entire process of geological warning, blasting control, and quality acceptance, "said the director of the Science and Technology Department of Three Gorges Group.

As night falls, the underground powerhouse of Nanzhang Power Station is still brightly lit. Li Zhenhua wrote in the construction log: "Today, the excavation and support of the second layer were completed, and the integrity of the rock mass was better than expected." He looked at the neat blasting marks on the tunnel wall, as if seeing the scene two years later, six units roaring and rotating, sending green electricity into the Central China Power Grid. Keywords: infrastructure engineering news, pumped storage power station

From the hinterland of Wuling Mountain to the Qinghai Tibet Plateau, these underground mega projects are quietly shaping the future of China's energy. With more projects reaching milestone breakthroughs in 2026, a safe, flexible, and green new power system is poised to take off.Editor/Yang Meiling